CVE-2021-21239

Open default xmlsec1 key-type preference

Severity Score

6.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability. Users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. PySAML2 does not ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only _x509 certificates_ for the verification process of the SAML document signature. This is fixed in PySAML2 6.5.0.

PySAML2 es una implementación de Python pura de SAML Versión 2 Estándar. PySAML2 versiones anteriores a 6.5.0, presenta una verificación inapropiada de una vulnerabilidad de firma criptográfica. Los usuarios de pysaml2 que utilizan el backend CryptoBackendXmlSec1 predeterminado y necesitan verificar los documentos SAML firmados están afectados. PySAML2 no garantiza que un documento SAML firmado esté correctamente firmado. El backend CryptoBackendXmlSec1 predeterminado está usando el binario xmlsec1 para verificar la firma de los documentos SAML firmados, pero por defecto xmlsec1 acepta cualquier tipo de clave que se encuentre dentro del documento dado. xmlsec1 debe configurarse explícitamente para usar solo _x509 certificates_ para el proceso de verificación de la firma del documento SAML. Esto es corregido en PySAML2 versión 6.5.0

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-12-22 CVE Reserved
2021-01-21 CVE Published
2023-11-30 EPSS Updated
2024-07-18 First Exploit
2024-08-03 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-347: Improper Verification of Cryptographic Signature

CAPEC

References (7)

URL	Tag	Source
https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0	Third Party Advisory
https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-5p3x-r448-pc62	Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00038.html	Mailing List
https://pypi.org/project/pysaml2	Product

URL	Date	SRC
https://github.com/RyanBoomer30/CVE-2021-21239-Exploit	2024-07-18
https://www.aleksey.com/pipermail/xmlsec/2013/009717.html	2024-08-03

URL	Date	SRC
https://github.com/IdentityPython/pysaml2/commit/46578df0695269a16f1c94171f1429873f90ed99	2021-03-10

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Pysaml2 Project Search vendor "Pysaml2 Project"		Pysaml2 Search vendor "Pysaml2 Project" for product "Pysaml2"				< 6.5.0 Search vendor "Pysaml2 Project" for product "Pysaml2" and version " < 6.5.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected